System and method for descrambling data

ABSTRACT

A method and system for negating a series of packed data bytes simultaneously based on conditional flags is used to descramble the data, as opposed to negating each byte with respect to each conditional flag bit. Sets of scrambled binary values are received. A descrambling code that corresponds to a flag bit sequence used to scramble the sets of binary values is generated. Then the sets of scrambled binary values are descrambled using the descrambling code. The method is particularly suitable for use in a wireless base band receiver.

BACKGROUND OF THE INVENTION

The present invention relates generally to communication systems andmore particularly, to descrambling scrambled data transmitted over acommunication channel.

In various contemporary communications systems such as code divisionmultiple access (CDMA), Worldwide Interoperability for Microwave Access(WiMAX), Global System for Mobile Communications (GSM), Long TermEvolution (LTE), and so forth, communication signals belonging tomultiple users are transmitted using shared frequency channels.Techniques, such as scrambling of the communication signals, are used toenable transmission of multiple user data on shared frequency channelswithout inter-user interference.

Scrambling user communication signals entails generating a uniquescrambling code (a predefined flag bit sequence) at a transmitter endcorresponding to the user. The scrambling code is used to encode thedigital equivalents of the communication signals to obtain scrambleduser data. The scrambled user data is transmitted to the receiver alongwith the scrambling code. Subsequently, the receiver decodes thescrambled data using the scrambling code to obtain descrambled data.

Scrambling may be accomplished by performing various mathematical andlogical operations on the user data and the scrambling code. Forexample, a logical bitwise XOR operation is performed at the transmitteron the user data and the scrambling code to obtain scrambled user data.The scrambled data is thereafter transmitted to the receiver. Theconversion of the analog user communication signals into scrambled userdata includes several processing stages such as cyclic redundancy check(CRC), channel coding, and rate matching. Scrambling is performed asdescribed above to obtain the scrambled user data. Further, modulation,precoding, and Radio Bearer (RB) mapping are performed on the scrambleddata before it is transmitted to the receiver.

At the receiver, the received signal is processed to recover thescrambled user data. Due to limitations in communication systems, theprobabilistic estimates for each recovered bit of the scrambled datasequence are obtained. The probabilistic estimates, also known as loglikelihood ratios (LLRs), soft values, or equalized demodulatedprobabilistic estimates, indicate the probability of whether a recoveredbit of a scrambled user data sequence is binary 1 or 0. Each probabilityestimate is represented in binary form using n bits, where n is apositive integer. After obtaining the probabilistic estimates,descrambling is performed to obtain the user data. The procedure used toperform descrambling depends on the scrambling procedure used. In theexample described above, when the user data is encoded by bitwiselogical XOR, the LLRs are negated based on the values of correspondingbits of the scrambling code used to recover the user data. Thus, an LLRis negated when the corresponding bit value of the scrambling code is 1and it is not negated when the corresponding bit value is 0.

The above descrambling operation including negation is performed byreading one bit of the scrambling code and a corresponding one LLR peroperational cycle. Then, based on the value of the scrambling bit, theLLR is negated. Since, the negation is performed by reading onescrambling bit and the corresponding one LLR per operational cycle, theprocess of descrambling requires many operational cycles for arelatively large number of sets of scrambled data. This leads to a highmillions of cycles per second (MCPS), which in turn increases executiontime.

It would be advantageous to improve the efficiency of the descramblingprocess, reduce MCPS, and decrease execution time.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of the preferred embodiments of thepresent invention will be better understood when read in conjunctionwith the appended drawings. The present invention is illustrated by wayof example, and not limited by the accompanying figures, in which likereferences indicate similar elements.

FIG. 1 is a schematic diagram illustrating a lookup table in accordancewith an embodiment of the present invention;

FIG. 2 is a flow chart illustrating a method for generating a lookuptable in accordance with an embodiment of the present invention;

FIG. 3 is a flow chart illustrating a method for descrambling one ormore sets of scrambled binary sequences in accordance with an embodimentof the present invention;

FIG. 4 is a flow chart illustrating a method for descrambling one ormore sets of scrambled binary sequences in accordance with an embodimentof the present invention; and

FIG. 5 is a system for descrambling one or more sets of scrambled binarysequences in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

The detailed description of the appended drawings is intended as adescription of the currently preferred embodiments of the presentinvention, and is not intended to represent the only form in which thepresent invention may be practiced. It is to be understood that the sameor equivalent functions may be accomplished by different embodimentsthat are intended to be encompassed within the spirit and scope of thepresent invention.

In an embodiment of the present invention, a method for descramblingsets of scrambled binary values is provided. The method includesreceiving a first predetermined number of sets of scrambled binaryvalues that were scrambled using a predefined flag bit sequence. Adescrambling code is generated by repeating each bit of the predefinedflag bit sequence for a second predetermined number that is equal to thebit length of a set of scrambled binary values. The first predeterminednumber of sets of descrambled binary values corresponding to the firstpredetermined number of sets of scrambled binary values is calculatedusing the at least one descrambling code and a predefined value. Thepredefined value is calculated using the first predetermined number andthe bit length of a set of scrambled binary values.

In another embodiment of the present invention, a method for generatinga lookup table used for descrambling one or more sets of scrambledbinary values is provided. The method includes generating binarycombinations, in which each binary combination has a bit length equal toa first predetermined number that is equal to a number of sets ofscrambled binary values to be descrambled, preferably simultaneously.Descrambling codes corresponding to the binary combinations aregenerated by repeating each bit of the binary combination for a secondpredetermined number that is equal to the bit length of a set ofscrambled binary values. Subsequently, the descrambling codes and thecorresponding binary combinations are stored as the lookup table.

In yet another embodiment of the present invention, a method fordescrambling one or more sets of scrambled binary values using a lookuptable is provided. The lookup table includes descrambling codes andbinary combinations. The method includes receiving a first predeterminednumber of sets of scrambled binary values to be descrambled, preferablysimultaneously. The first predetermined number of sets of scrambledbinary values is scrambled using a predefined flag bit sequence.Thereafter, a descrambling code corresponding to a binary combination isaccessed from the lookup table, in which the binary combination isidentical to the predefined flag bit sequence. Subsequently, the firstpredetermined number of sets of descrambled binary values correspondingto the first predetermined number of sets of scrambled binary values iscalculated using the descrambling code and a predefined value. Thepredefined value is calculated using the first predetermined number andthe bit length of a set of scrambled binary values.

In still another embodiment of the present invention, a method fordescrambling one or more sets of scrambled binary values using a lookuptable is provided. The lookup table includes descrambling codes andbinary combinations. The method includes receiving a first predeterminednumber of sets of scrambled binary values to be descrambled. The firstpredetermined number of sets of scrambled binary values is scrambledusing a predefined flag bit sequence. Thereafter, a descrambling codecorresponding to a binary combination is accessed from the lookup table,in which the binary combination is identical to the predefined flag bitsequence. A first intermediate value is then calculated by ANDing thedescrambling code and a predefined value, in which the predefined valueis calculated using the first predetermined number and the bit length ofa set of scrambled binary values. A second intermediate value iscalculated by XORing the first predetermined number of sets of scrambledbinary values and the descrambling code. Thereafter, the firstintermediate value is added to the second intermediate value to obtainthe first predetermined number of sets of descrambled binary valuescorresponding to the first predetermined number of sets of scrambledbinary values.

In an embodiment of the present invention, a system for descramblingsets of scrambled binary values is provided. The system includes aprocessor for descrambling the sets of scrambled binary values andgenerating a descrambling code corresponding to the predefined flag bitsequence by repeating each bit of the predefined flag bit sequence for apredetermined number, in which the predetermined number is equal to thebit length of a set of scrambled binary values. A memory including alookup table is coupled to the processor. The lookup table includes atleast one binary combination and the at least one descrambling codecorresponding to the at least one binary combination.

Various embodiments of the present invention provide a system and amethod for descrambling sets of scrambled binary values. The methodincludes receiving sets of scrambled binary values that are to bedescrambled substantially simultaneously. Thereafter, descrambling codesare either generated or accessed from a lookup table. Subsequently, thesets of scrambled binary values are descrambled, preferablysubstantially simultaneously, using a predefined flag bit sequence usedfor scrambling at a transmitter. Since the various sets of scrambledbinary values are scrambled simultaneously, the descrambling operationis very efficient, which leads to improvement in MCPS and reduction inexecution time.

Referring now to FIG. 1, a schematic diagram illustrating a lookup table100 in accordance with an embodiment of the present invention is shown.The lookup table 100 includes columns 102 a, and 102 b and rows 104 a,104 b, 104 c, and 104 d.

Column 102 a includes binary combinations, in which each binarycombination has a bit length equal to a first predetermined number, m.The first predetermined number m is equal to the number of sets ofscrambled binary values that are to be simultaneously descrambled. In anembodiment of the present invention, the first predetermined number m isa positive integer that can have any value depending on a systemimplementation. In one example, m=4 and the sets of scrambled binaryvalues are binary representations of the probabilistic estimatescorresponding to a scrambled user data sequence.

The scrambled user data sequence is obtained by encoding a user data bitstream into a scrambled user data sequence at a transmitter using apredefined flag bit sequence. In a wireless system, the scrambled userdata sequence is then transmitted to the receiver in the form ofelectromagnetic waves. In an embodiment of the present invention, theencoding is accomplished by performing a bitwise logical XOR operationon the user data sequence and the predefined flag bit sequence. Thereceiver then recovers the scrambled user data sequence. It should beunderstood by persons skilled in the art that the probabilisticestimates, also known as log likelihood ratios (LLRs), soft values, orequalized demodulated probabilistic estimates, indicate the probabilityof whether a recovered bit of a scrambled user data sequence is binary‘1’ or ‘0’. The probabilistic estimates are subsequently processed fordescrambling scrambled user data. Column 102 b includes descramblingcodes that correspond to each binary combination. The method forgeneration of the descrambling codes is explained in detail inconjunction with FIG. 2.

Referring now to FIG. 2, a flow chart illustrating a method forgenerating a lookup table in accordance with an embodiment of thepresent invention is shown. At step 202, binary combinations aregenerated in which each binary combination has a bit length equal to thefirst predetermined number m. The binary combinations are obtained bygenerating various possible unique binary sequences that can be obtainedcorresponding to a binary sequence having a bit length equal to m.Therefore, the number of unique binary combinations obtainedcorresponding to a binary sequence of bit length m is 2^(m). Each uniquebinary combination is identical to a predefined flag bit sequence (of apredetermined bit length) that may have been used to scramble the userdata at a transmitter. Scrambling includes encoding a user data bitstream into a scrambled user data sequence at a transmitter using thepredefined flag bit sequence. The encoded data is then transmitted tothe receiver. In an embodiment of the present invention, the encoding isaccomplished by performing a bitwise logical XOR operation on the userdata sequence and the predefined flag bit sequence.

At step 204, descrambling codes are generated corresponding to eachbinary combination. The descrambling codes are generated by repeatingeach bit of the binary combination for a second predetermined number k.The second predetermined number is equal to the bit length of a set ofscrambled binary values. In an example, when m=4, k=8, and one of thebinary combinations is ‘0001’ (cell of the lookup table 100corresponding to the column 102 a and row 104 b), the hexadecimalequivalent of the corresponding descrambling code is ‘0x00 00 00 FF’(cell 102 b, 104 b of the lookup table 100). Similarly, the descramblingcodes corresponding to the remaining binary combinations in rows 104 a,104 c, and 104 d are generated. Since, each binary combinationcorresponds to a predefined flag bit sequence, generating descramblingcodes corresponding to each binary combination enables simultaneousdescrambling of sets of scrambled binary values. At step 206, the lookuptable 100 including the binary combinations and the correspondingdescrambled codes is stored in a memory.

Referring now to FIG. 3, a flow chart illustrating a method fordescrambling one or more sets of scrambled binary values in accordancewith an embodiment of the present invention is shown.

At step 302, a first predetermined number m, of sets of scrambled binaryvalues to be simultaneously descrambled is received at a receiver. In anembodiment of the present invention, the first predetermined number is apositive integer which can have any value depending on systemimplementation. In an example, m=4. Further, the sets of scrambledbinary values are binary representations of the probabilistic estimatescorresponding to a scrambled user data sequence, in which the scrambleduser data has been scrambled using a predefined flag bit sequence at atransmitter. In an embodiment of the present invention, each set ofscrambled binary values has a bit length equal to a second predeterminednumber k. In an embodiment of the present invention, the predefined flagbit sequence is transmitted from the transmitter to the receiver alongwith the scrambled user data for enabling descrambling of the scrambleduser data. Further, it should be understood by persons skilled in theart that the probabilistic estimates indicate the probability of whethera recovered bit of a scrambled user data sequence is binary ‘1’ or ‘0’.Therefore, each LLR corresponds to a bit of the scrambled user datasequence transmitted from the transmitter to the receiver. Further,since one bit of the predefined flag bit sequence was used to scrambleone bit of the user data at the transmitter, each LLR (a set ofscrambled binary values) is descrambled using a corresponding bit of thepredefined flag bit sequence. In an embodiment of the present invention,the probabilistic estimates are at least one of LLRs, soft values, orequalized demodulated probabilistic estimates.

At step 304, a descrambling code is generated corresponding to thepredefined flag bit sequence. Since, each bit of the flag bit sequencecorresponds to a set of scrambled binary values to be simultaneouslydescrambled, the bit length of the flag bit sequence is equal to thenumber of sets of binary values received by the receiver, i.e., m. In anexample, m=4. The generation of the descrambling code entails repeatingeach bit of the predefined flag bit sequence for a second predeterminednumber, i.e., k, in which the second predetermined number is equal tothe bit length of a set of scrambled binary values. In an example, k=8.The method followed for generation of the descrambling code is identicalto the generation of a descrambling code corresponding to a binarycombination that has been explained in conjunction with step 204 (FIG.2).

At step 306, the first predetermined number of sets of descrambledbinary values corresponding to the first predetermined number of sets ofscrambled binary values is calculated. In an embodiment of the presentinvention, the descrambling of the sets of scrambled binary valuesentails negating or not negating each set of scrambled binary valuesbased on the value of a corresponding bit in the predefined flag bitsequence. In accordance with this method, a set of scrambled binaryvalues is negated when the corresponding flag bit is binary ‘1’ else theset of scrambled binary values is not negated. The above calculation isperformed using the descrambling code generated corresponding to thepredefined flag bit sequence and using a predefined value, CVALUE. In anembodiment of the present invention, CVALUE is calculated using thefirst predetermined number, m, and the bit length of a set of scrambledbinary values, k. The predefined value may be calculated using thefollowing equation:

$\begin{matrix}{{CVALUE} = {\sum\limits_{i = 0}^{m - 1}2^{ik}}} & (1)\end{matrix}$

where CVALUE is a hexadecimal equivalent of the right hand side ofequation (1). Therefore, when m=4 and k=8, CVALUE=‘0x1010101’. Themethod for calculation of the first predetermined number of sets ofdescrambled binary values is explained in detail with reference to FIG.4.

Referring now to FIG. 4, a flow chart illustrating a method fordescrambling one or more sets of scrambled binary values in accordancewith another embodiment of the present invention is shown. FIG. 4 willbe now explained in detail in conjunction with FIGS. 1 and 3.

At step 402, a first predetermined number, i.e., m, of sets of scrambledbinary values to be simultaneously descrambled is received at areceiver. Step 402 is identical to step 302, which has been explained indetail in conjunction with FIG. 3. In an example, m=4 and therefore foursets of scrambled binary values are received. An exemplary group of foursets of scrambled binary values, in which each set of scrambled binaryvalues is eight (8) bits long is illustrated in Table A below:

TABLE A 11110010 00100011 10010000 01110010

At step 404, a descrambling code corresponding to a binary combinationfrom the lookup table is accessed, in which the binary combination isidentical to a predefined flag bit sequence used to scramble the m setsof scrambled binary values at a receiver end. For example, ‘0010’ may bethe predefined flag bit sequence used to obtain the sets of scrambledbinary values illustrated in Table A. Therefore, the descrambling codecorresponding to the binary combination ‘0010’ is accessed from thelookup table 100, i.e., ‘00000000 00000000 11111111 00000000’. Asdescribed previously, a set of scrambled binary values is negated basedon the value of a corresponding flag bit of the predefined flag bitsequence. When the flag bit is ‘1’, the set is negated and vice versa.Thus, in the above example, the scrambled set corresponding to the flagbit having value ‘1’ will be negated and the remaining sets will not benegated. In an embodiment of the present invention, the descramblingcode may be generated corresponding to the predefined flag bit sequenceduring the run time execution of the various described methods in amanner as described in conjunction with step 304. In such a scenario thelookup table 100 is not generated.

At step 406, a first intermediate value IVALUE₁ is calculated byperforming a bitwise logical AND operation on the descrambling code anda predefined value CVALUE. CVALUE is calculated using m, and the bitlength of a set of scrambled binary values k. Calculation of the CVALUEwas explained in detail in conjunction with step 306, in accordance withwhich CVALUE=‘0b00000001 00000001 00000001 00000001’ corresponding tom=4 and k=8. In an embodiment of the present invention, CVALUE may begenerated and stored prior to the run time execution of the variousdescribed methods. In another embodiment of the present invention,CVALUE is generated during run time execution using the values of m andk. Thereafter, bitwise logical AND operation is performed. In anexample, using the exemplary values of the descrambling code asmentioned in step 404, and of the CVALUE as mentioned above yieldsIVALUE₁=‘00000000 00000000 00000001 00000000’.

At step 408, a second intermediate value IVALUE₂ is calculated byperforming a bitwise logical XOR operation on the first predeterminednumber of sets of scrambled binary values and the descrambling code. Inan example, using the exemplary values of sets of scrambled binaryvalues as illustrated in Table A, and of the descrambling code asmentioned in step 404, IVALUE₂=‘11110010 00100011 01101111 01110010’. Atstep 410, the first intermediate value IVALUE₁ is added to the secondintermediate value IVALUE₂ to obtain the first predetermined number ofsets of descrambled binary values corresponding to the firstpredetermined number of sets of scrambled binary values. Each set ofdescrambled binary values of the first predetermined number of sets ofdescrambled binary values is obtained simultaneously, thereby enablingdescrambling of the second predetermined number of sets of scrambledbinary values in one operational cycle. Using the exemplary values ofIVALUE₁ and IVALUE₂ as calculated in the above examples, the firstpredetermined number of sets of descrambled binary values obtained areillustrated in table B below:

TABLE B 11110010 00100011 01110000 01110010

It will be understood by persons skilled in the art that the third setof descrambled binary values from left in the Table B is the negatedversion of the third set of scrambled binary values from left in TableA. This is in accordance with the predefined flag bit sequence ‘0010’,in which the third flag bit from the left is 1.

Referring now to FIG. 5, a system 500 for descrambling one or more setsof scrambled binary values in accordance with an embodiment of thepresent invention is shown. The system 500 includes a processor 502 anda memory 504. In one embodiment of the invention, the processor 502 andmemory 504 are part of a wireless base band receiver and the scrambleddata is data received from a wireless base station. However, as will beunderstood by those of skill in the art, the present invention is notlimited to wireless base band receivers.

The processor 502 receives the sets of scrambled binary values. The setsof scrambled binary values are binary representations of theprobabilistic estimates corresponding to a scrambled user data sequence,in which the scrambled user data has been scrambled using a predefinedflag bit sequence at a transmitter. In an embodiment of the presentinvention, the predefined flag bit sequence is transmitted from thetransmitter to the receiver along with the scrambled user data forenabling descrambling of the scrambled user data at the receiver.Thereafter, the processor 502 descrambles the sets of scrambled binaryvalues using the steps or a combination of steps described inconjunction with FIGS. 2, 3, and 4. The processor 502 is coupled to thememory 504. The memory 504 stores a lookup table generated using thesteps as described in conjunction with FIGS. 1 and 2. In anotherembodiment of the present invention, when the descrambling codes aregenerated during the run time execution of the various methods presentlydescribed, the memory 504 is not required, since in such a scenario alookup table is not generated.

As will be understood by those of skill in the art, the presentinvention may be implemented in hardware, software, or a combination ofhardware and software. When implemented in software (i.e., a computerprogram), the software usually will be stored on an internal memory ofthe processor. Thus, in one embodiment the present invention provides acomputer program stored on a non-transitory computer readable medium fordescrambling one or more sets of scrambled binary values using a lookuptable (LUT). The LUT includes descrambling codes and a plurality ofbinary combinations. The computer program includes first programinstructions that receive a first predetermined number of sets ofscrambled binary values that were scrambled using a predefined flag bitsequence. Second program instructions access at least one descramblingcode from the LUT corresponding to a binary combination that isidentical to the predefined flag bit sequence. Third programinstructions calculate a first intermediate value by performing abitwise logical AND operation on the at least one descrambling code anda predefined value. The predefined value is calculated using the firstpredetermined number and the bit length of a set of scrambled binaryvalues. Fourth program instructions calculate a second intermediatevalue by performing a bitwise logical XOR operation on the firstpredetermined number of sets of scrambled binary values and the at leastone descrambling code. Fifth program instructions add the firstintermediate value to the second intermediate value to obtain the firstpredetermined number of sets of descrambled binary values correspondingto the first predetermined number of sets of scrambled binary values.

While various embodiments of the present invention have been illustratedand described, it will be clear that the present invention is notlimited to these embodiments only. Numerous modifications, changes,variations, substitutions, and equivalents will be apparent to thoseskilled in the art, without departing from the spirit and scope of thepresent invention, as described in the claims.

1. A method for descrambling data, wherein the data includes one or moresets of scrambled binary values, the method comprising: receiving afirst predetermined number of sets of scrambled binary values that werescrambled using a predefined flag bit sequence; generating at least onedescrambling code by repeating each bit of the predefined flag bitsequence for a second predetermined number that is equal to the bitlength of a set of the scrambled binary values; and calculating a firstpredetermined number of sets of descrambled binary values correspondingto the first predetermined number of sets of scrambled binary valuesusing the at least one descrambling code and a predefined value, whereinthe predefined value is calculated using the first predetermined numberand the bit length of a set of scrambled binary values.
 2. Thedescrambling method of claim 1, wherein each bit of the predefined flagbit sequence corresponds to at least one set of scrambled binary values.3. The descrambling method of claim 2, wherein descrambling comprisesnegating a set of scrambled binary values based on the value of acorresponding bit in the flag bit sequence.
 4. The descrambling methodof claim 1, wherein each set of scrambled binary values is at least oneof a log likelihood ratio (LLR), a soft value, and an equalizeddemodulated probabilistic estimate.
 5. The descrambling method of claim1, wherein calculating the first predetermined number of sets ofdescrambled binary values comprises calculating a first intermediatevalue by performing a bitwise logical AND operation on the at least onedescrambling code and the predefined value.
 6. The descrambling methodof claim 5, wherein calculating the second predetermined number of setsof descrambled binary values further comprises performing a bitwiselogical XOR operation on a set of scrambled binary values and the atleast one descrambling code to obtain a second intermediate value. 7.The descrambling method of claim 6, wherein calculating the secondpredetermined number of sets of descrambled binary values furthercomprises adding the first intermediate value to the second intermediatevalue.
 8. A method for descrambling one or more sets of scrambled binaryvalues using a lookup table, the lookup table comprising a plurality ofdescrambling codes and a plurality of binary combinations, the methodcomprising: receiving a first predetermined number of sets of scrambledbinary values to be descrambled simultaneously, wherein the firstpredetermined number of sets of scrambled binary values are scrambledusing a predefined flag bit sequence; accessing at least onedescrambling code from the lookup table corresponding to a binarycombination, wherein the binary combination is identical to thepredefined flag bit sequence; and calculating the first predeterminednumber of sets of descrambled binary values corresponding to the firstpredetermined number of sets of scrambled binary values by using the atleast one descrambling code and a predefined value, wherein thepredefined value is calculated using the first predetermined number andthe bit length of a set of scrambled binary values.
 9. The descramblingmethod of claim 8, wherein each bit of the predefined flag bit sequencecorresponds to at least one set of scrambled binary values.
 10. Thedescrambling method of claim 9, wherein descrambling comprises negatinga set of scrambled binary values based on the value of a correspondingbit in the flag bit sequence.
 11. The descrambling method of claim 8,wherein each set of scrambled binary values is a log likelihood ratio(LLR), a soft value, and an equalized demodulated probabilisticestimate.
 12. The descrambling method of claim 8, wherein calculatingthe first predetermined number of sets of descrambled binary valuescomprises calculating a first intermediate value by performing a bitwiselogical AND operation on the at least one descrambling code and thepredefined value.
 13. The descrambling method of claim 12, whereincalculating the second predetermined number of sets of descrambledbinary values further comprises performing a bitwise logical XORoperation on a set of scrambled binary values and the at least onedescrambling code to obtain a second intermediate value.
 14. Thedescrambling method of claim 13, wherein calculating the secondpredetermined number of sets of descrambled binary values furthercomprises adding the first intermediate value to the second intermediatevalue.
 15. A method for descrambling one or more sets of scrambledbinary values using a lookup table, the lookup table comprising aplurality of descrambling codes and a plurality of binary combinations,comprising: receiving a first predetermined number of sets of scrambledbinary values to be descrambled simultaneously, wherein the firstpredetermined number of sets of scrambled binary values are scrambledusing a predefined flag bit sequence; accessing at least onedescrambling code from the lookup table corresponding to a binarycombination, wherein the binary combination is identical to thepredefined flag bit sequence; calculating a first intermediate value byperforming a bitwise logical AND operation on the at least onedescrambling code and a predefined value, wherein the predefined valueis calculated using the first predetermined number and the bit length ofa set of scrambled binary values; calculating a second intermediatevalue by performing a bitwise logical XOR operation on the firstpredetermined number of sets of scrambled binary values and the at leastone descrambling code; and adding the first intermediate value to thesecond intermediate value to obtain the first predetermined number ofsets of descrambled binary values corresponding to the firstpredetermined number of sets of scrambled binary values.
 16. Thedescrambling method of claim 15, wherein scrambling comprises encoding abit stream into the first predetermined number of sets of scrambledbinary values using the predefined flag bit sequence, wherein each bitof the predefined flag bit sequence corresponds to a bit of the bitstream.
 17. The descrambling method of claim 16, wherein each bit of thepredefined flag bit sequence corresponds to at least one set ofscrambled binary values.
 18. The descrambling method of claim 17,wherein descrambling comprises negating a set of scrambled binary valuesbased on the value of a corresponding bit in the flag bit sequence. 19.The descrambling method of claim 15, wherein each set of scrambledbinary values is a log likelihood ratio (LLR).